I have heard that there is an Eastern Pureland (Medicine Buddha) as spoken in the sutras. Or Maitreya Buddha's pureland (though Im not sure if Tusita is a pureland).

How come most people do not vow to be reborn in let's say, Bhaisajyaguru's pureland. I have heard that rebirth in these purelands, one can still fall back into samsara. But someone else said no, because it's still a pureland.

It's got a lot do to with the complex history of Buddhism in Central and East Asia, which groups of people followed which teachings, and who had the ability to put their favorite teaching into the dominant position.

Amongst the nomadic peoples, such as the Turkic groups, the Mongols, and Jin and Liao, all to the north of China, there was a huge amount of devotion towards Maitreya. The Han later turned more towards Amitabha, for a number of reasons. Many Maitreya devotion groups were downright outlawed - it is easy for a rebellious group to claim that their leader is Maitreya, a powerful move; one can't really do that with Amitabha.

Teachings about Bhaisajyaguru were a bit later anyway, and likewise other Pureland notions, so didn't get the same foot hold. The eastern world of Aksobhya has pretty high entry criteria, so was unlikely to be that popular from the outset.

All the Pure Lands of the Buddhas of the ten directions have equal qualities and virtues. Their Dharma Nature is also the same. Therfore, the practitioner should meditate on all the virtues of the Buddhas and seek rebirth in the various Pure Lands of the ten directions. Why should he specifically seek rebirth in the Pure Land of one particular Buddha (i.e., Amitabha)? Is this not contrary to the truth of "equally in seeking rebirth"? Answer

All the Pure Lands of the Buddhas are, in truth, equal. Nevetheless, since the majority of sentient beings in our world generally have dull faculties and defiled, scattered minds, it will be difficult for them to achieve samadhi, unless they concentrate exclusively on one realm.

The practice of constantly focussing on Amitabha Buddha is the "Single Mark Samadhi". Because the Mind is exclusively devoted to one thing, the practitioner achieves rebirth in the Pure Land. In the Sutra Rebirth According to One's Vows, Buddha Sakyamuni was asked by a Bodhisattva, "Honored One! There are Pure Lands in all ten directions. Why do you especially extol the Western Pure Land and urge sentient beings to focus continuously on Amitabha Buddha, seeking rebirth in His Land?"

The Buddha replied, "Sentient beings in this Saha World generally have polluted, scattered minds. Therefore, I only extol one Pure Land in the West, focussing their Minds on a single realm. If they meditate on all Buddhas, the scope of attention will be too broad, their Minds will be lost and scattered and they will find samadhi difficult to attain. Thus, they will fail to achieve rebirth in the Pure Land.

"Furthermore, seeking their virtues of one Buddha is the same as seeking the virtues of all Buddhas -- as all Buddhas have one common Dharma Nature. That is why to focus on Amitabha Buddha is to focus on all Buddhas, to be born in the Western Pure Land is to be born in all Pure Lands."

Thus, the Avatamsaka Sutra states:

"The bodies of all the Buddhas / are the body of any one Buddha. / They have the same Mind and the same wisdom. / They are also equal in power and fearlessness."

The Avatamsaka Sutra further states:

"It is like the full moon, round and bright, its image reflected in all rivers and ponds. Although the reflection is everywhere, there is but a single moon. So it is with ... (the Buddhas). Although they appear in all realms, their bodies are non-dual."

In summary, based on these examples, the wise will understand the truth that "one is all, all is one". When this truth is grasped, concentrating on one Buddha is precisely concentrating on all Buddhas.

Sonrisa wrote:I have heard that there is an Eastern Pureland (Medicine Buddha) as spoken in the sutras. Or Maitreya Buddha's pureland (though Im not sure if Tusita is a pureland).

How come most people do not vow to be reborn in let's say, Bhaisajyaguru's pureland. I have heard that rebirth in these purelands, one can still fall back into samsara. But someone else said no, because it's still a pureland.

Can anyone explain?

I've asked this question myself. Really despite Amitabha's vows, it really depends which Buddha you have a connection with. For me it's Medicine Buddha and I vow everyday to be born into the Eastern Pureland of Pure Azure Radiance. No Buddha, no matter whatever pureland known or unknown to us would let you fall from their guidance, once you're in the work to bring you to enlightenment begins, not to send you back to a life of suffering.